Wax-thread sewing-machine



Ei WOODWARD. WAX THREAD SEWING MACHINE.V

Patented Sept. 20, 1881'.

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UNTTED STATES PATENT OFFICE. A'

ERASTUS WOODVABD, OF BOSTON, ASSIGNOR TO GEORGE W. OOPELAND,

TRUSTEE, OF MALDEN, MASSACHUSETTS.

WAX-THREAD SEWING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 247,285, d

ated September 20, 1881.

Application filed September 8, 1880. (Model.)

.To all whom it may concern Be it known that I, ERAsTUs WooDWAnD, ofBoston, in the county of Suffolk and Commonwealth of Massachusetts, haveinvented an Improvement in Wax Thread Sewing -Machines, ot which thefollowing is a specification.

This invention has for its object the following-described improvements in wax-th read sew- Io ing-machines. lt is an improvement upon thesewingmachine shown and described in Letters Patent, Reissue No. 6,535,granted Gordon McKay and RobertH. Mathies,assignors, dated July 6,1875.It embraces, first, means where.-

by the length of stroke of the needle-bar is determined by the positionof the presser-foot; second, means whereby the cast-off bar is adjustedautomatically by the needle-bar and presser-foot. j Referenceis madetothe accompanying drawings, forming a part of this specification, inexplaining the nature of the invention, in

whichl Figure l is a front elevation of my improvement. Fig. 2 is a viewpart in side elevation and part in section. Fig. 3 is a view partly inplan and part-ly in section upon the line yy of Fig. l. Fig. 4 is across-section on the line zz of Fig. 2. Fig. 5 represents certaindetails of construction. Fig. 6 is a view representing a friction-blockattached to the needle-bar, and adapted to be placed in positionthereon, according to the thickness of the work, by the presser-foot, ina manner substantially as hereinafter set forth. l y

In wax-thread sewing-machines having a stationary rest or bed for thework, organized for sewing material of varyin g thicknesses with achain-stitch, it is necessary to vary the length of thread used inmaking a stitch as the sewing progresses from thin to thick work, andvice versa, and this variation must be eli'ected by the needle.Therefore, as more thread :is used in sewing thick work, the needle-barmust have a greater throw than in sewing thin work. The needle mustalways descend to the same base-line, and consequently the variation inthe length of stroke of the'needle-bar must be from that line upward. Itis also desirable to connect the cast-0E with the needle-bar andpresser-foot, so that the movements given the cast-off may beautomatically determined by them and be obtained by simple mechanism.

A represents the cam for operating the needle-bar. -The lever B connectsthe cam with the link b, which is pivoted at its lower end by the stud bto the block b2, through which the needle-bar passes, and to whichV itis fastened by means of the set-screw b3. The said lever -B is pivotedat bl to a sliding sleeve, b5, which is adapted to have a limitedmovement upon the rod b against the stress of spring 117, as hereinafterexplained. The stop bs, fastened Yto said rod bythe set-screw b9, servesto adjust said sleeve, and consequently the fulcrum of thelever, in itsproper position. f The presserfoot bar C is provided with the projectingarm c, which is arranged to slide on the rod b", against the pressure ofthe spring bl, before named, and in addition is provided with a bracketor arm, c', having a recess, c2, which receives a stud, c3, fastened toa friction-block, c, through whichthe needle and cast-off bars c c2pass. The presser-foot-bar has also an arm, c5, which projects over the'end of the 75 lever B. t

The operation of this part of my mechanism, lby which a varying strokeis provided the needle-bar governed by the presser-foot, is as follows:l The cam A is cut to provide the needlebar, by its connectingmechanism,with a throw that will be sufficient for drawing the threadnecessary for making a stitch in the thickest material. The pivot bfinthis instance will-be stationary. For sewing work of less thickness theneedle-bar is not provided with so great a stroke, and this isaccomplished by causing the arm c5 to act as a stop, against which theend of the lever B comes in contact, thereby causing the fulcrum b4 ofthe lever B to yield downwardly. Ot' course, the higher the arm or stopc5 the less the downward movement of the fulcrum and the greater-thethrow of the needle-bar. The presser-foot bar is operated by a cam orany other suitable mechanism, and as it lifts from the work it compresses the spring 127, and also adjusts the arm or stop c5 to aposition to which the end 'of the lever B may arise before the fulcrumb4 takes up the lost motion.

The block c4 is provided with a friction-plug, c6, which is forcedinwardly against the cast- IOO off bar by means of the spring c,fastened to the block. The needle-bar moves freely in the block. Thisconstruction provides for an upward movementJ of the cast-off bar, forreasons hereinafter explained.

Below the friction-block c4 there is arranged another friction-block, D,which is similar in construction to the one first described 5 but thefriction-plu g, instead ot bearin g upon thecast- 0E bar, bears upon theneedle-bar, and the cast-off bar is arranged to move freely therein.

Below the last-named friction-block there are two blocks, d d', whichare fastened by setscrews to the cast-off bar.

The operation of the needle-bar, cast-oft' bar, and presserfoot toaccomplish the proper movements of the cast-otrn in relation to those ofthe needle-bar or needle is as follows: The needle-bar is lifted a shortdistance, equal in extent to the thickness of the workand the extent ofthe needle below the surface-plate to the barb. The cast-off bar is thenstarted and'moved upwardly at the same rate of speed with the needle-baruntil the highest point of the needle-bar stroke is reached. Theneedlebar is then moved downwardly sufficiently to uncover the barb, andthe cast-oft bar is then moved simultaneously with the needle-bar untilit reaches the surface of the work.

As it is essential that the needle-bar have a varying extent of throw,and as the presserfoot,while it lifts a uniform distance from thesurface of the work, yet by the variations in the thickness of the workhas an irregular throw from the work-plate of the machine, it isnecessary to provide a compensating mechanism whereby the'cast-oii barmay continue to have the same relative movements with the needle-barwhile the variations in the length of throw are transpiring. In order tounderstand this portion of my mechanism it is necessary to bear in mind,rst, that the cast-off bar is lifted by the needle-bar by means of theblock' b2, fastened to the needle-bar, and the block d', fastened to thecast-olic bar, the said block d being so placed as to allow the cast- 0Eto descend to the lowest position in which it can be used; second, thatthe friction-block c, which is positively moved by thepresserfoot-operating mechanism, is so attached to the cast-off bar thatwhile it allows the same to be moved therein when positively actuated,it also, by means of suitable frictional mechanism, operates at certaintimes to hold the same, so that upon the upward movement of thepresser-foot bar the cast-oif bar is moved upward; and, third, thatthefriction-block D, attached to the needle-bar, and the block d,attached to the cast-oft' bar, serve to lower the cast-od' bar.

The position of the friction-block D upon the needle-bar is changedautomatically durfl ing the upward stroke of the needle-bar and cast-offbar by contact with the upper block, c4, (which is held stationary whilethe needle-bar continues to rise,) and thereby, upon the downwardmovement of the needle-bar, by contact with the block d, moves thecast-oif to the surface ofthe work. As it is necessary, however, thatthe needle should commence to descend before the cast-off, that the barbof the needle may be uncovered, the cast-oft bar is retained by thefriction-block c4 in its highest position, while the needle-bar is moveddownwardly a short distance. The cast-off bar is then caused to descendsimultaneously with the needle-bar by the regulating block D, which,moving down with the needle-bar, comes in contact with the block d. Thisregulating-block is always placed in position by the block c4 upon itsupward movement, so that the space between it and the block d determinesthe extent of downward movement of the needle-bar before the cast-olfbar is operated. The friction block c4 also holds the cast-od inposition upon the work until it is positively lifted upon the upwardmovement of the needle-bar by the blocks b2 and d. The friction-pluginthe block D must bear with greater force or stress against theneedle-bar than the friction-plug in the block c4 bears against thecast-oi bar, in order that the said block D in its downward movement maydraw the cast-od bar with it and not slip on the needle-bar.

It will be noticed that the lost motion or compensation, whereby themovementl of the cast-off bar is not increased during the increasedmovement of the needle-bar, is obtained or e'ected by the regulatingblock D, which is adjusted by contact with the block c* to a givenposition upon the needle-'bar in relation to the block d at everyupwardmovement, and which also comes to rest when the cast-off reachesthe work,while the needle-bar continues to descend, thereby taking upthe difference of movement between the twobars,

IOO

both at the end of the downward and upward stroke thereof.

To guard against the yielding or spring of 'any part of theneedle-drivingl mechanism while the needle is in the work, I provide thelever B with a curved arm, E,the end of which rides upon the stationaryblock c from the time when the needle is about to enter the material onits downward stroke until it has cleared it upon its upward, therebyholding the fulcrum b4 in a fixed position during this part of themovement of the needle-bar. The tripping of this locking-arm upon thefurther upward movement of the needle-bar leaves the fulcrum b4 andsliding sleeve b5 free to be moved downwardly against the stress of thespring; yet such downward movement will not take place to any extentuntil the outer end of the lever-bar comes in contact with the stop c5.

It will be observed that the mechanism for effecting the variations vinthe stroke of the needle-bar is very simple, and that upon the contactof the outer end ofthe lever with the lstop c5 the fulcrum of the leveris changed from the pivot b4 to its outer end, and the pivot b4 and thesupporting sleeve yield downwardlyg also, that the position ofthe stopc5 is automatically fixed by the presser-foot; also, that the cast-ofi'is actuated by the needle-bar IIO and presser-foot bar through themedium of intermediate compensating frictional mechanism.

F is the needle; G, the cast oft', H, the presser-foot.

The rod b6 may be adjusted vertically by means of suitable adjusting-screws, thereby adjusting the stop 118.

The cam for operating the mechanism reciprocating the needle is soshaped that the needle-bar starts slowly and has a graduallyaccelerating movement, in order that the strain upon the thread may notbe severe at the commencement of the upward movement of the needle.

It will be noticed that the spring Z7 not only serves to automaticallyreturn the sliding sleeve b5 to its original position on each throw ofthe needle-bar, but that it also acts to hold down the presser-bar;also, that the higher the presser-foot is lifted thevless the slidingsleeve is depressed, and therefore the strain upon the spring during alldepressionsis very nearly uniform.

The operation of my mechanism has been eX- plained coincidently with itsdescription.

The presser-foot may be held down by an iudependent spring in lieu ofthe spring 117, if desired.

Having thus fully described my invention, I claim and desire to secureby Letters Patent of the United States- 1. In a wax-threadsewing-machine, the combination of the cam A, the lever B,the needlebarC', the devices connecting the end ot' the lever with the needle-bar,with the sliding lever supporting sleeve b5, and the stop e5, adapted tobe placed in position by the material sewed, substantially as and forthe. purposes described.

2. In a wax thread sewingmachine, as a means ot' varying the stroke ofthe needle-bar, the lever B, adapted to be operated by a cam, andmechanism, substantially as specied, placed-in position by the work fortransferring the fulcrum of the lever from or near its center to itsouter end, all substantially as and for the purposes described.

3. In awax-thread sewing-machine, the combination of a lever, B, forreciprocating the needle-bar, pivoted at b4 to the sliding sleeve b5,the said sliding sleeve b5, the spring b", and

4the stop c5, all substantially as and for the purmachine, of a lever,B, for operating the needle-bar, with a yielding sleeve, b5, to whichthe lever is pivoted, andrmeans for reciprocating the lever, allsubstantially as described.

6. In a wax-thread sewing-machine, the combination of the presser-footbar, adapted to be lifted a uniform distance from the level of the work,and provided with the stop c5, and arm C, with the lever B, the slidingsleeve b5, spring bl, and cam A, all adapted to operate substantially asset forth.

7. The block D, frictionally attached to the needle bar, in combinationwith the presserfoot and connecting mechanism, whereby the block isplaced in position upon the needle-bar according to the thickness of thework, all substantially as and for the purposes speciied.

8. The combination, in a wax-thread sewingmachine, of a needle-bar andcast-od' bar, and block D, frictionally attached to the needlebar, andplaced in position thereon by the presser-foot, and the block el,rigidly fastened to the presser-foot bar, all adapted to automaticallyregulate the downward motion of the cast-off bar, all substantially asand for the purposes described.

9. In a wax-thread sewing-machine, the block n b?, attached to theneedlebar, the block d', fastened to the cast-off bar, the irictionalblock c4, positively actuated by the presser-foot and frictionallyattached to the castoft' bar, the friction-block D, and the block d,attached to the cast-oft' bar, all adapted to operate to automaticallyvary the throw of the cast-off bar, substantially as described.

ERASTUS WOODWARD.

Witnesses:

F. F. RAYMOND, 2d, A. J. GETTING-ER.

